In the use of microwave ovens, which are installed in homes, restaurants and other commercial establishments, it is not uncommon for the food items being heated or cooked to overflow slightly or splatter within the microwave oven chamber. Usually, the oven chamber is defined by walls of a plastics material or metal such as stainless steel, and have smooth inner surfaces to facilitate cleaning of the wall surfaces after the oven has been used for some period of time. The cleaning operation is usually performed manually with a sponge and a detergent solution and must be performed frequently if the microwave oven receives extensive use, for example, in a commercial kitchen or in association with food vending machines. In such uses and in some home uses, considerable time and effort are required to maintain the microwave oven chamber in a clean and sanitary condition.